Crud Controller

CrudController.java

public abstract class CrudController<T extends Model> {
    
    protected Form<T> form;
    private Template1<Form<T>,Html> composeTemplate;
    private Template1<T,Html> showTemplate;
    private Template2<T,Form<T>,Html> editTemplate;
    private Template1<List<T>,Html> listTemplate;
    private Finder<Long,T> finder;

    public CrudController(Class<T> clazz, 
                Template1<List<T>,Html> listTemplate, 
                Template1<Form<T>,Html> composeTemplate, 
                Template1<T,Html> showTemplate, 
                Template2<T,Form<T>,Html> editTemplate, 
                Finder<Long,T> finder) {
                    
        this.form = Controller.form(clazz);
        this.listTemplate = listTemplate;
        this.composeTemplate = composeTemplate;
        this.showTemplate = showTemplate;
        this.editTemplate = editTemplate;
        this.finder = finder;
    }
    
    
    protected abstract T createFromForm(T element, Long... preIds);
    
    protected abstract Call redirectToItem(T element);
    protected abstract Call redirectToList();
    
    protected T getFromId(Long id) {
	return finder.byId(id)
    };
    
    
    
    public final Result list() {
        return Controller.ok(listTemplate.render(finder.all()));
    }
    
    public final Result compose() {
        return Controller.ok(composeTemplate.render(form));
    }
    
    public final Result create() {
        ...
        return Controller.redirect(redirectToItem(newElement));
    }
    
    public final Result item(Long id) {
        T element = getFromId(id);
        if (element==null) return Controller.notFound();
        return Controller.ok(itemTemplate.render(element));
    }
    
    public final Result edit(Long id) {
        ...
        return Controller.ok(editTemplate.render(form.fill(element), element));
    }
    
    public final Result update(Long id) {
        ...
        return Controller.redirect(redirectToItem(editedItem));   
    }
    
    public final Result delete(Long id) {
        ...
        return Controller.redirect(redirectToList());
    }
    
}

Non-static-Tags.java

@MinRole(User.Role.Admin)
public class TagCrudController extends CrudController<Tag> {

    public TagCrudController() {
        super(Tag.class, list.ref(), compose.ref(), item.ref(), edit.ref(), Tag.find)
    }
    
    @Override
    protected Tag createFromForm(Tag element) {
        return Tag.create(element.tag);
    }

    @Override
    protected Call redirectToItem(Tag element) {
        return routes.Tags.crud.item(element.id);
    }

    @Override
    protected Call redirectToList() {
        return routes.Tags.crud.list();
    }
    
    public Result search(String term) {
        return Controller.ok(searchResults.render(finder.where().eq("tag",term).findList()))
    }
    
    
}

static-Tags.java

public class Tags extends Controller {

    //@MinRole(User.Role.Admin) // does not work at the moment
    public static final CrudController<Tag> crud = 
		new CrudController<Tag>(Tag.class, list.ref(), compose.ref(), item.ref(), edit.ref(), Tag.find) {

        @Override
        protected Tag createFromForm(Tag element) {
            return Tag.create(element.tag);
        }

        @Override
        protected Call redirectToItem(Tag element) {
            return routes.Tags.crud.item(element.id);
        }

        @Override
        protected Call redirectToList() {
            return routes.Tags.crud.list();
        }
        
        // method will not be found by routes file, because this method is not part of CrudController
        public Result search(String term) {
            return Controller.ok(searchResults.render(finder.where().eq("tag",term).findList()))
        }
        
    };
    
}